[Dovecot] Using custom Maildir subfolders with pop3 deliveri

Greetings, I am trying to make my antispam protection on user basis. So I need something like .junkmail folder in every user maildir. But the problem I am having is that my mail client can not download mail put in .junkmail folder. I am usin POP3 only, Maildir mailboxes (default_mail_env = maildir:/var/mail/%u) and whether I make folder with leadin dot or not it is never shown in mail client. Sincerely I don`t even know if it is posible with POP3, but it would be very hard converting to IMAP at this moment. Thanks in advance.